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Experimental verification of the mechanisms of shock waves acceleration of volcanic particles toward metal targets: a tool to understand shock waves hazard in explosive volcanic eruptions (SPAEx)
Date du début: 15 avr. 2009, Date de fin: 14 avr. 2012 PROJET  TERMINÉ 

Despite shock waves commonly occur during explosive volcanic eruptions, a number of issues concerning their generation and propagation is still object of debate in the scientific community and the associated hazard is downplayed in the risk assessment of active volcanic areas. Micrometric impact craters produced by volcanic ash particles were found on a steel basketball pole in one of the villages destroyed by the 1982 eruption of El Chichón volcano (Mexico). The velocities of impacts, calculated by analytical methods, showed typical shock waves values up to 980 m/s. The research topic outlined in this proposal is the experimental acceleration of volcanic particles of different size and mass toward steel targets by shock waves produced by a rapid decompression of a pressurized system (fragmentation bomb). Research questions to be answered are: a) which is the role of the gas phase in accelerating particles by the rapid expansion produced by a shock wave? b) Which is the role of particles’ size and/or mass in the acceleration mechanism? c) What is the importance of the impact angle in the magnitude of the craters produced? The results expected will contribute to a better understanding of the mechanisms of shock waves propagation during explosive eruptions and inspire further investigations to improve hazard mitigation strategies.

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